Journal of the Japan Society of Engineering Geology
Online ISSN : 1884-0973
Print ISSN : 0286-7737
ISSN-L : 0286-7737
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Volume 45, Issue 4
Displaying 1-4 of 4 articles from this issue
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  • Measuring Thermal Diffusivity of Rock Core and Rock Mass by using the Optional Heating Method
    Tadao IMAI, Shinji YAMAGUCHI, Naoto KAMOSHIDA, Fumio SUGIMOTO
    2004 Volume 45 Issue 4 Pages 174-182
    Published: October 10, 2004
    Released on J-STAGE: February 23, 2010
    DOIhttps://doi.org/10.5110/jjseg.45.174
    JOURNAL FREE ACCESS
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    The purpose of this study is to develop a method of measuring thermal diffusivity in rock core and rock mass by the optional heating method without the restriction of heating conditions. The conventional method of measuring thermal diffusivity in rock has many restrictions of heating conditions, such as form of specimen, adiabatic condition and so on. Therefore, we cannot easily measure thermal diffusivity in rock core and rock mass.
    In the measurement method proposed in this paper, rock core is heated from its surface and the temperature in the core is measured. Then, its thermal diffusivity is calculated from the change in the temperature by the proposed method. Furthermore, this technique is applied to rock mass. In the in-situ measurement, holes are drilled in the rock mass, in which a cylindrical heater and thermocouples are inserted. By this method, it is possible to investigate an effect of discontinuity surface in rock mass.
    The results of the experiments show that the appropriate thermal diffusivity of rock can be obtained by using the proposed method, and also reveal that the thermal diffusivity of rock mass tends to decrease remarkably owing to discontinuity in rock mass.
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  • Alluvium Stratigraphy and Engineering Geology in the Hachinohe City
    Ko SATO
    2004 Volume 45 Issue 4 Pages 183-191
    Published: October 10, 2004
    Released on J-STAGE: February 23, 2010
    DOIhttps://doi.org/10.5110/jjseg.45.183
    JOURNAL FREE ACCESS
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    Alluvial deposits occupy from the surface to 45 meters below the sea level around the Hachinohe City, and they are lithologically divided into the Konakano, Naganawashiro and Ruike Formations in ascending order. The Konakano Formation consists of basal gravel, sand and silt. The Naganawashiro Formation consists of graded sand and marine clay in which sometimes shell fragaments and pumice are observed. The Ruike Formation is composed of various kinds of sediments including organic remain and fossils which indicate 5, 280±100y. B. P. by the carbon-14 ages.
    Also the data of wells reveal the details of buried terraces, buried talus and several buried sand-gravel strata. The buried river terrace surfaces are present in three levels. They are the higher surface (The Kawaragi Surface) of 5-14 meters below the sea level, the middle surface (The Tamonoki Surface) of 5-21 meters below the sea level and the lower surface (The Nakui Surface) of 24-37 meters below the sea level in respective heights.
    The decision of bearing stratum for civil construction is under the control of vertical and horizontal distribution of Alluvial gravels and clayey sediments. For example, in case of small scale construction, the bearing stratum can be decided on a graded bedding of the Naganawashiro Formation which indicates a series of column of gravel, sand and clayey sediments in ascending order. On the contrary, in case of large scale construction, it is necessary for the bearing stratum to examine the subsidence for consolidation of clayey sediments, and to perforate until basal gravels of the Konakano Formation or Diluvium including buried river terrace deposits.
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  • Microscopic Visualization in Rocks under Confining Pressure by Means of Micro Focus X-Ray CT
    Manabu TAKAHASHI, Takato TAKEMURA, Masaji KATO
    2004 Volume 45 Issue 4 Pages 192-196
    Published: October 10, 2004
    Released on J-STAGE: February 23, 2010
    DOIhttps://doi.org/10.5110/jjseg.45.192
    JOURNAL FREE ACCESS
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    To visualize the microstructure in rocks under confining pressure, micro focus X-ray CT system that can get three dimensional data simultaneously with high resolution of 10 micron is introduced. A new pressure vessel for micro focus X-ray CT that can be pressurized up to high confining pressure of 100MPa is developed. Using this pressure vessel, the aperture changes of preexisting fracture in the fault related granite and in cored mudstone were observed. Aperture decreased firmly with increasing confining pressure. The multi planar reconstruction images enable us to distinguish well between individual grains and pore space. It was found that the micro focus X-ray CT with the newly designed pressure vessel, provides a useful information about individual particles, voids and cracks as a non-destructive visualizing tool.
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  • My Practical Know-how of Route Selection for Tunneling
    Hiroshi OSHIMA
    2004 Volume 45 Issue 4 Pages 197-209
    Published: October 10, 2004
    Released on J-STAGE: February 23, 2010
    DOIhttps://doi.org/10.5110/jjseg.45.197
    JOURNAL FREE ACCESS
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    [in Japanese]
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